Diarrhea (cont.)

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What symptoms are associated with diarrhea?

The symptoms that are associated with diarrhea depend on the cause and type of diarrhea.

If there is a large secretory component to the diarrhea the bowel movements are frequent and watery. Pain is not common, and there are no signs of inflammation.

Similarly, an osmotic diarrhea is watery, but its main characteristic is that once ingestion of food stops (which would include the offending dietary food or substance that is not digested or absorbed) the diarrhea stops.

Motility related diarrhea is more likely to be associated with cramping abdominal pain.

Inflammatory diarrhea often is associated with crampy abdominal pain as well as signs of inflammation, for example, fever and abdominal tenderness. It also may be associated with intestinal bleeding, either with visible blood in the stool or invisible blood that only is detected by testing the stool for blood.

Although one might expect the diarrhea of collagenous colitis to be painless (since diarrhea is believed to be due to poor absorption of fluid and electrolytes), in fact, it is frequently associated with abdominal pain, suggesting that there is more to collagenous colitis than a failure to absorb fluid and electrolytes.

What are common causes of acute diarrhea?

The most common cause of acute diarrhea is infection--viral, bacterial, and parasitic. Bacteria also can cause acute food poisoning. A third important cause of acute diarrhea is starting a new medication.

Traveler's diarrhea

There are many strains of E. coli bacteria. Most of the E. coli bacteria are normal inhabitants of the small intestine and colon and are non-pathogenic, meaning they do not cause disease in the intestines. Nevertheless, these non-pathogenic E. coli can cause diseases if they spread outside of the intestines, for example, into the urinary tract (where they cause bladder or kidney infections) or into the blood stream (sepsis).

Certain strains of E. coli, however, are pathogenic (meaning they can cause disease in the small intestine and colon). These pathogenic strains of E. coli cause diarrhea either by producing toxins (called enterotoxigenic E. coli or ETEC) or by invading and inflaming the lining of the small intestine and the colon and causing enterocolitis (called enteropathogenic E. coli or EPEC). Traveler's diarrhea usually is caused by an ETEC strain of E. coli that produces a diarrhea-inducing toxin.

Tourists visiting foreign countries with warm climates and poor sanitation (Mexico, parts of Africa, etc.) can acquire ETEC by eating contaminated foods such as fruits, vegetables, seafood, raw meat, water, and ice cubes. Toxins produced by ETEC cause the sudden onset of diarrhea, abdominal cramps, nausea, and sometimes vomiting. These symptoms usually occur 3-7 days after arrival in the foreign country and generally subside within 3 days. Occasionally, other bacteria or parasites can cause diarrhea in travelers (for example, Shigella, Giardia, and Campylobacter). Diarrhea caused by these other organisms usually lasts longer than 3 days.